What doesn't work about windows snapping? I've never had any issues doing win+shift+arrowsCosmic will likely overtake KDE but it's not there yet, maybe in 1-2 years. My issues were Chrome doesn't go into dark mode, windows snapping not really working yet, need to change mouse settings in config files as many thing missing in the settings, various other issues.
I will be checking out future updates though.
I don't think cosmic will replace kde, more like it's a viable replacement for gnome.